1. Field of the Invention
The present invention relates to a substrate process apparatus.
2. Description of the Related Art
At a photo resist coating step of a semiconductor fabrication, resist is coated as a resist film on the front surface of for example a semiconductor wafer (hereinafter referred to as wafer). A pattern is exposed on the resist film. The pattern is developed on the wafer with developing solution. Such a sequence of processes is performed by a coating/developing apparatus.
The coating/developing apparatus is composed of various units such as a cooling unit, a heating unit, a resist coating unit, and a developing unit. The cooling unit cools a wafer. The heating unit heats a wafer. The resist coating unit coats resist solution to a wafer. The developing unit develops a patter on a wafer. To compactly structure the coating/developing apparatus, a plurality of heating units and cooling units are piled up as a heat treatment unit group. In the heat treatment unit group, heating units are disposed above cooling units so as to prevent heat interference. In a conventional coating/developing apparatus, a heat treatment unit group and a conveying unit are disposed in the vicinity of the resist coating unit and the developing unit so as to further reduce the space of the apparatus.
However, as the size of a wafer becomes large, the size of the required process apparatus becomes large. To reduce the space of the apparatus, it is necessary to further integrally dispose each process unit. However, when heating units become large, the amount of heat generated therefrom become large. Thus, when heating units as process units of the heat treatment unit group are disposed in the vicinity of a resist coating unit, heat generated therefrom may cause the film thickness of a resist film to vary.